Retractable core barrel



Nov. 25, 1941. A. MUHL BACH 2,263,639

' RETRACTABLE CORE BARREL Filed July 25, 1939 A 2 Sheets-Sheet l I iii [Z N v E N TO K '74/6CQ/ Maw/back AT TORNEY 2 Sheefs-Sheet 2 A. MUHLBACH Filed July 25, 1939 RETRACTABLE CORE BARREL an I mm M M m m m l, w uwMUHHHHWMMMM%W%AA-4% m v w v,

Nov. 25, 1941.

- are substantially increased.

Patented. Nov. 25, 1941 UNITED, STATES? PATENT or-Frcn I. m a aanmnn it mrea'rrumtun Low melee, chug five-eighth: to mane: Bi. 0mm. Whittier,"

Calif.

Application July 25,,1a39; sum no; 206,356.

(cuss-42y This invention relates to a retractable core" barrel and is a continuation-in part ot:an.appli.-- cation flied in the name of Altred'Muhlbach, on

December 24, 1938, SerialNo, 247,625, entitled "Core barrel? .In the art of deep oil wells, it is known to provide core drills with a detachable core barrel which may be removed by means of a wire line after a full core has been.

taken, and to be replaced by an empty corebarrel, thus enabling drilling to continue; without removing the drill string until the bit becomes dull or other exigencies require it.

It is a principal object 01" this invention to:

provide an improved core barrelvoi such retract"- able type.

It is another object of this invention to provide a core barrel for usewith a core drill,- hav.

ing relatively rotatable inner and outer shells, whereby the outer shell may rotate with the core drill and the inner shell which receives thecore are carried by the barrel so as to be retractable w'ell drilling, particularly" this inventionv topro-- Fig. 3. is'a cross section asseenon planet-8 Fig; 4 is an axialsectionthrough the core bar.-

rel on. an enlarged scale;

Fig. 5 is a sectionsimilar to Fig. 2 but showing the meansby.- which. they cable for moving. the core barrel is attached to the core barrel;

v Fig. 6 isacrosssection as seen on plane 6A oili'ig. 2; and I Fig. 7 is an-elevation .of'the overshot used. tor gripping the upper end of the corebarrel as sembly;

Referring to the drawings-tithe core drill is generally indicated by l0; and includes a tubular drill stem i ll arranged'to be secured to the lower end of a drillstring. inithe conventionalmanner,

as by a threaded connection, one member of whichis indicatediby II on the-drill stem ll;

The-drill stem carries an appropriate cutter. or. hit l3 of any preferred form at its lower end;

A: core barrel I l is mounted. in; the; drill. stem H for receiving. the core. The corebarrel ll seatsihbit l3 andiisdetachably held'thereonby means of latch mechanism: generally: indicated? Latch mechanism l5 includes a releasing member l6. (Figs; 1 and 2) whichis arrangedto connect with a' suitable tool. attached to the end therewith. 'Since' these teeth are subject to severe wear, it is of advantage tobe able toremove and replace the cutter which carries them withp out pulling the drill. string. By this means, theintervals between such replacement operations It is still another object of this invention to provide improved latch means for anchoring the core barrel in the stem of the core drill.

This invention possesses many other advantages, and has otherobjectswhich may bemade more easily apparent from a considerationofone embodiment of the invention. For this purpose there is shown a form in. the drawings accompanying and forming part of, the present specification. This form will now'be described in detail, illustrating the general principles ofthe invention: but it is to be understood that this detailed description is not to be taken in a-iimitinq sense, since the scope of this invention is best deflned'by the appended claims.

In the drawings: Figure 1 is an axial section of a core drill including the improved core barrel;

Fig. 2 is an axial section through the upper part of the core drill, on an enlarged. scale, as seen on plane 2-! of Fig. 1;

of a wire line or cable. When: an upward force is exerted" onthis'member, the latches are re.-

' tracted.. Thus'with the cable conected to member IS, an. upward pull will first. disengage the latches, and then lift the barrel'out' oi the drill stem. Or a barrel may be lowered into place;

as soon as it seats, the latches engage; the cable may then be disconnected. and withdrawn.

As previously mentioned, the bit llimaybe of any preferred 'form, but it must have an axial opening 20, through; which the lower end of the barrel it extends. This barrel. seats on a seat 2| surroundingthe opening. In the present instance, the. outer annulus of" the bore is cut by a bit, shown of the wing type, and having a number of fixed cutting blades 22.

' By referring to Fig; 4'- it 'will be seen thatthe core barrel H has an inner shell and. an outer shell 26,. these. shells being relatively rotatable.

The outer shell" has anextensionzl threadedly secured to its lower end; Thisextension or cutter 21 extends through opening 20 in bit It and terminates in cutting teeth 28 which cooperate with blades 22? for cutting'the. core. The upper end oi cutter 21 has an enlargedportionor collar 29 into which shell 28 screws and which provides a shoulder "(which rests on. seat '21. This serves to support barrel II! on bit IS. The upper end of shell 26 is closed by cap 3| threadedly engaging the shell 26 and having an upper extension 32 (Fig. 2) threadedly secured to it.

Appropriately secured in an extension of the threaded box |2, as by welding, is a ring 33 which closely embraces the upper part of extension 32 and serves to maintain barrel "l4 substantially coaxial with stem |l. Ring 33: pr,ovides a downwardly directed shoulder 34' which cooperates with latch means l to hold barrel l4 against movement in the drill stem II. V The upper extension 32 is provided with a transverse slot 35 for accommodating latch memb'ers 36 and 31, forming the latch means l5. Members 36 and 31 are substantially identical and are supported in member 32 by a pin 38 near their lower ends. Each member has an upwardly directed shoulder 39 adapted to pass under ring 33 and engage the shoulder 34 when the members are in their outer or engaging position. Members 36 and 31 are urged apart to their outer engaging position by a compression spring 46 confined between them. in suitable recesses 4|.

(see Fig. 2).

The upper part of each latch member is reduced in width as indicated at 42 and has portions of its outer, surface oppositely inclined as-at '43 and 44. The release member l6 has a hollow cylindrical portion 45 which embraces the upper ends 420! the latch members. It is provided withslots- 46 inclined on their lower surfaces to cooperate with the inclined surfaces 44. The arrangement issuch that with member l6 in its normal position, that is with no upward pull on it,.the parts occupy the position of Fig. 2, member |6 acting to limit the outward movement of latch members 36 and 31. r

- when an upward pull is exerted on the release member [6,. the inclined surfaces 44 slide on the inclined lower surfaces of slots 46, the latch members 36 and 31 swinging toward each other 1 about pin 38. until the backsof extensions 42 contact. checking. the ,movement of the members.

- the rotation of shell 26, an inner shell 25 is provided which remains stationary with the core to protect it. This inner shell carries a core catcher' 5| (Fig. 4) at its lower and provided with spring fingers 52 for retaining the core in a well understood manner. The core catcher 5| provides an annular surface 53 which rests on a shoulder 54 formed in cutter 21 for supporting shell 25. Since the thrust on the innershell 25 is mostly upward, due to the downward travel of the core barrel over a stationary core, an anti-friction thrust bearing 55 is provided at the upper end of shell 25. Thelower race 56 of this hearing is secured on the upper end'of the shell, the upper race 51 being in contact with a cage 58 slidably supported.

in the outer shell 26. A compression spring 58 in cap 3| urges cage 58, bearing 55, and shell 25 downwardly and is effective to maintain surfaces 53 and 54 resiliently in contact. By this 'arrangement, the need of adjustments to maintain proper clearance between these surfaces is elimiadapted to be secured to a drill string, an annunated., Further, ability to absorb shocks due to the entering core, is provided.

To permit the usual circulation fluid to reach the cutting surfaces of bit l3, this is provided with several ports, as indicated by 60 (Figs. 1 and 4), the circulation reaching these through the annular space between core barrel l4 and drill stem l I. To allow the circulation freely to pass ring 33, this may have a plurality of holes 6| (Fig. 3).

Any fluid which may be trapped in the inner shell 25 above the entering core can pass out of this shell through holes 62 provided at its upper end into the space between shells 25 and 26, from where it can pass into the space within the tubular stem and bit through openings 63.

By referring to Figs. 2 and 5, it will be noted that the releasing member l6 has a frusto-conical portion 65 terminating in a neck 66 provided with a head 61 forming a downwardly directed shoulder 68. In Figs. 5 and 7 an overshot 10 is shown which is especially arranged for use with member I6 to provide means for coupling a wire line or cable to it, as well as for releasing it at will.

This overshot 10 has a cylindrical body 1| with a lower portion 12 of enlarged diameter having a bore 13 to accommodate head 61. The lower end of bore 13 is tapered as at 14 to fit conical surface 65. The upper end of body 1| has a threaded pin 15 by which the overshot may be connected to a cable 16, it being understood that a suitable rope socket 11, sinker bar 18, or other suitable apparatus may be interposed between the overshot and the cable.

Body 1| is provided with a long transverse slot in which are mounted a pair of similar arms 8| and 82 on a pivot pin 83. Each of arms 8|, 82 has a depending hook 84 provided with a barb 85 and upward extension 86. A compression spring 81 is confined between these extensions and serves to urge the hooks 84 together. A stop pin 88 is provided to prevent the hooks approaching each other too closely.

When the overshot 16 is lowered over the release member |6, the conical surface 14 will serve to center the overshot by contacting head 61, spreading the hooks until the barbs 85 pass below it, when spring 81 will be eilective to urge the barbs under shoulder 68. Release member I6 is now attached, by means of the overshot to line 16, an upward pull on which will release the latch means I5 as previously described so that the core barrel H can be pulled to the surface. When desired, the core barrel l4 can be detached from the overshot 10 by pressing the upper ends 86 of arms 8| and 82 together by means of a suitable tool. This spreads barbs 85 so that head 61 can pass between them. Another core. barrel can then be dropped or otherwise lowered in the well, circulation fluid being utilized if ,necessary to properlyseat it in the core drill. Obviously, a core barrel can be removed and replaced as often as. desired without disturbing the drill string.

What is claimed is:

l. A core drill including a tubular drill stem lar cutter on said stem, and a core barrel having driving connection betweenv the stem and the barrel when the barrel is seated, said means serving to support the barrel when the barrel is lifted and an outer shell arranged for relative rotation.

2. A core drill including a tubular drill stem adapted to be secured to a drill string, an annular cutter on said stem, a core barrel for receiving a core and movable through the drill string, said core barrel having an outer shell arranged to seat in said annular cutter, and an inner shell rotatably supported within the outer shell, and releasablemeans for maintaining the outer shell on its seat. i

3. A core drill including a tubular drill ste adapted to be secured to a drill string, an annular cutter on said stem, 9, core barrel movable through the drill string and arranged to be supported in the drill stem for receiving a core, said core barrel having an inner shell and an outer shell arranged for relative rotation, said outer shell seating in said cutter, cutting means on the outer shell for forming a core, a driving connection between the outer shell and the stem, and means to maintain said shell on its seat.

4. A- retractable core barrel'including an outer shell, a cutter'adapted to form a core secured to said shell, an inner shell rotatably supported at its lower end by the cutter, and a bearing support for the upper end of the inner shell car-- ried by the outer shell.

5. A core drill including a tubular drill stem the upwardly directed shoulders are arranged to' inner shell in said outer shell;

, adapted to be secured to a drill string, an annular cutter on said stem, a core barrel movable through the drill string and arranged to be supported in the drill stem for receiving a core, and means to maintain the core barrel against upward movement, comprising: a pair of latch members pivoted adjacent the upper end oi the core barrel and arranged to swing outwardly, each member having an upwardly directed shoulder, means forming an annular downwardly directed shoulder in the drill stem under which engage, each latch member having an upward extension with' an inclined outer surface, a release memberencompassing said extensions and having surfaces cooperating withthe extensions to swing the latchmembers-inward in response to upward movement or the release member.

, 6. In a retractable core barrel, ;movable through a-"drill string and adapted to be supported in a drill stem for receiving a -cor'e,'an inner shell and an outer shell, said outer shell carrving means for cutting the core, means forming a seat for supporting the outer shell, means for releasably securing the outer shell on its seat, said means also providing a driving' means for the outer shell, and means rotatably supporting the ALFlgEDIMUHIBACHE 

